Nonblocking sharethis script load

    <script>
        (function(o) {
            var switchTo5x=true;
            a=o.getElementsByTagName('head')[0];
            r=o.createElement('script');
            r.onload = function(){
                stLight.options({publisher: "<some_hash>", doNotHash: false, doNotCopy: false, hashAddressBar: false});
            };
            r.async=1;
            r.src='http://w.sharethis.com/button/buttons.js';
            a.appendChild(r);
        }(document));
    </script>